125 g / 1 stick salted butter, (softened until it's squishy, but not too melted. If you are using unsalted butter, then add 1/4th tsp salt)
½ cup sugar
1 egg yolk
1 tsp vanilla essence
1 heaped cup sifted flour ( I used 1 cup +1 tablespoon)
¼ cup Nutella to spread, a little more won’t hurt, but be careful not to overdo lest it ooze!
2-3 tablespoon, toasted, chopped hazelnuts ( Optional- I think for a neater swirl, these can be omitted, else chop them really fine, even pulse them in the food processor or mixie for a few seconds. Other wise you can sprinkle the nuts on top of the cooki